Pressure Regulator

ABSTRACT

A pressure regulator comprising a housing containing a channel arranged to communicate a fluid from a fluid inlet to a fluid outlet, said channel comprising a valve seat and closure member with said closure member operable with valve seat to control fluid flow through the channel and; wherein the housing comprises a resilient diaphragm member in fluid communication with the fluid and in physical communication with the closure member such that the diaphragm member is operable to deform in response to a change in pressure of the fluid and such that deformation of the diaphragm member causes the closure member to change position and; wherein that the regulator comprises a deflection member located in the channel and arranged to deflect fluid flowing in the channel such that the closure member is shielded to substantially prevent fluid, that is flowing generally parallel to the movement axis of the closure member, and in a downstream direction, from impinging on the portion of the closure member that is upstream of the valve seat.

FIELD

This invention relates to a pressure regulator for controlling fluidpressure. Particularly, but not exclusively, the invention pertains tominiature pressure regulators for medical devices.

BACKGROUND

Pressure regulators for use in medical devices such as a gas deliverysystem often require high accuracy of the regulated output pressure. Inrecent years there has been a move towards miniaturisation and weightreduction of medical devices including devices using pressure regulatorsto allow for increased convenience and portability. Accordingly therehave been attempts to produce miniature pressure regulators to satisfythese size and weight requirements including single stage regulators foruse with supply pressures of typically 4-10 bar, producing a reducedregulated output pressure. Such single stage miniature pressureregulators may also have applicability in scientific equipment and highprecision industrial machinery.

“Pressure droop” is a characteristic seen in known regulators wherebythe pressure at the regulator outlet falls, deviating away from the setpoint pressure as the flow rate through the regulator is increased.

In seeking to reduce the size of pressure regulators the size often hasto be compromised to achieve the required regulator performanceparticularly for increased flow capacity and the reduction of outlet“pressure droop”—typically by increasing the size of regulator toachieve the performance requirement. The present invention seeks toprovide a compact pressure regulator and/or in which pressure droop ismitigated.

SUMMARY

According to the present invention there is provided a pressureregulator, said pressure regulator comprising a housing containing achannel arranged to communicate a fluid from a fluid inlet to a fluidoutlet, said channel comprising a closure member operable with a valveseat to control the flow of fluid through the regulator from inlet portto outlet port, wherein the housing comprises a resilient diaphragmmember in fluid communication with the fluid and in physicalcommunication with the closure member such that the diaphragm member isoperable to deform in response to a change in pressure of the fluid andsuch that deformation of the diaphragm member causes the closure memberto change position; and wherein that the regulator comprises adeflection member located in the channel that is arranged to deflectfluid flowing in downstream direction in the channel such that theclosure member is shielded to substantially prevent fluid flow that isgenerally parallel with the movement axis of the closure member, fromimpinging on surfaces of the closure member that are upstream of thevalve seat.

By this approach, the use of the deflection member to provide shieldingallows the magnitude of forces urging the closure member towards thevalve seat along the movement axis of the closure member to be reduced,thereby reducing the outlet pressure droop. This reduction in pressuredroop in turn allows the flow capacity of the pressure regulator to beincreased.

Furthermore, the use of such a deflection member allows for a compactconfiguration of pressure regulator. The structural approach ofproviding a deflection member in this way facilitates a low-costmanufacturing approach while providing reduction of outlet pressuredroop.

Beneficially the deflection member deflects fluid around the closuremember such that fluid is directed to the valve seat via apertures orslots in the deflection member in a generally symmetric manner in aplane substantially perpendicular to the movement axis of the closuremember.

In some examples, the movement axis of the closure member may besubstantially coaxial with the fluid inlet. Additionally oralternatively, the deflection member may be located in the channelproximate to the fluid inlet. Such a configuration allows for a compactconfiguration of pressure regulator.

In some examples, the closure member maybe an elongate element. Such astructure allows the closure member to be in physical communication withthe diaphragm element in a simplified manner while at the same timebeing operable to open and close the channel

In some examples, the fluid inlet may be substantially parallel to thefluid outlet.

Alternatively, the fluid inlet may be substantially perpendicular to thefluid outlet. Such a configuration allows for a compact configuration ofpressure regulator.

In some examples, the regulator may comprise a bias spring to bias theclosure member into abutting the diaphragm. Such a structure allows theclosure member to remain in physical communication with the diaphragmand to apply a force to the diaphragm.

Furthermore such a configuration allows for physical contact to bemaintained in a manner which simplifies manufacture and/or assembly.

In some examples, the closure member may be fixedly attached to thediaphragm. Such a configuration allows the closure member to remain inphysical communication with the diaphragm and allows the application ofa bias force to the closure member acting towards the diaphragm to beavoided. In some examples, the closure member may be removably attachedto the diaphragm. Such a configuration allows the closure member toremain in physical communication with the diaphragm and allows theapplication of a bias force to the closure member acting towards thediaphragm to be avoided. Furthermore such a configuration allows theremovability of the closure member such that it can be replaced forrepair.

In some examples, the diaphragm may be biased by a force acting on thediaphragm by a diaphragm load spring to urge the diaphragm and thereforethe closure member towards a position that provides an opening betweenthe closure member and the valve seat. Such a structure allows a forceto be applied to the diaphragm through the selection of the springstiffness and length and the magnitude of spring compression.

In some examples, the regulator may comprise an adjustment mechanismwhich is operable to adjust the compression of the diaphragm load springsuch that the force acting on the diaphragm by the diaphragm load springcan be varied. Such a structure allows for an end user to adjust thefluid output pressure.

In some examples, a section of the diaphragm which is not in fluidcommunication with the channel may have a fluid communication path tothe exterior of the pressure regulator to the exterior environment. Sucha structure allows for fluid pressure on the channel side of thediaphragm to be referenced to the exterior pressure. In some examples,the pressure of a pressurised control fluid acting on the side of thediaphragm which is not in contact with the channel may be adjusted tovary the force of the pressurised control fluid acting on the diaphragm.Such a configuration allows an end user to adjust the regulator fluidoutlet pressure.

In some examples, the fluid pressure at the fluid outlet may bedetermined by a net spring force acting on the diaphragm. Such aconfiguration allows for the fluid outlet pressure to be predeterminedin a simplified manner without the need for elements other than thediaphragm and those producing a force on the diaphragm to be adjusted.

In some examples, the net force acting on the closure member maycomprise two or more forces selected from the group comprising: therestoring force of the resilient diaphragm itself; a force appliedthrough the closure member by the bias spring; the force applied by thediaphragm load spring; and the force applied by a pressurised controlfluid. Such a configuration allows for the pressure regulator to beadjusted by adjusting the force acting on the diaphragm from one or moreof the elements making up the net force. Furthermore such aconfiguration allows for pressure regulators to be used for a wide rangeof applications.

In some examples, the pressure regulator may be a non-relieving pressureregulator. Such a configuration allows for fluid wastage to be reducedand allows for the release of potentially dangerous fluids to bereduced.

In some examples, the pressure regulator may be a relieving pressureregulator. Such a configuration allows the relief of excess pressureabove a set point in the event of induced pressure from a system ordevice connected to the regulator outlet

In some examples, the wetted components of the pressure regulator may besuitable for use with medical gases. Such a configuration allows suchpressure regulators to be used for a wide range of applications, inparticular for use in medical applications.

Some examples provide a multi-stage pressure regulator wherein at leastone stage of the multi-stage pressure regulator is a regulator accordingto the invention.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the present invention will now be described in greaterdetail with reference to the accompanying drawing in which:

FIG. 1a shows an end view of a pressure regulator;

FIG. 1b shows a lengthwise cross-section through the pressure regulatorshown in FIG. 1 a; and

FIG. 1c shows an enlarged portion of the cross-section through thepressure regulator shown in FIG. 1 b.

While the invention is susceptible to various modifications andalternative forms, specific embodiments are shown by way of example inthe drawings and are herein described in detail. It should be understoodhowever that the drawings and detailed description attached hereto arenot intended to limit the invention to the particular form disclosed.

DETAILED DESCRIPTION

An example of a pressure regulator is illustrated in FIGS. 1a -1 c. Thepressure regulator shown in FIGS. 1a-1c has a main body 10, into whichis assembled a valve structure that includes a movable closure member 14(also known, for example, as a valve poppet), a valve seat 17 and avalve seat housing 12. The valve seat housing 12 is dimensioned toreceive valve seat 17 which in the present example is an elastomericflat disc with an aperture. The closure member 14 is movable underaction of the regulator mechanism described below to move along amovement axis so as to in one position cause obstruction of a fluid pathand in other positions provide restriction to the fluid path.

To allow the fluid path to be opened, the closure member 14 is moved toa position where a gap is provided between the aperture of the valveseat 17 and the closure member 14 such that the fluid path is open.

In the example structure illustrated in FIGS. 1a -1 c, the closuremember 14 is assembled into the pressure regulator by way of beinginserted into a receiving structure of the main body 10 along with aclosure member housing 11, a bearing 15, a bias spring 16, the closuremember 14, the valve seat 17, a valve seat housing 12, and a retainer13. The bore in the retainer 13 and the bore in the bearing 15 aredimensioned to slidably receive the closure member to provide guidancefor the closure member along an axis coaxial with the valve seat andvalve seat housing. The bias spring 16 registers against a shoulder onthe closure member 14 and against a shoulder on the bearing 15 toprovide an urging or biasing force acting on the closure member 14towards the valve seat 17. The retainer 13 has a threaded portion thatengages with the main body 10 and is torque tightened to secure thevalve seat housing 12, the valve seat 17, the closure member 14, thebias spring 16, the bearing 15 and the O ring seal 32 in position in themain body 10. The structure of the main body 10 together with theretainer 13 and the orifice plug 31 provides a partition between themain fluid path and the diaphragm. The chamber between the saidpartition and diaphragm is referred to as the diaphragm chamber 76.Fluid communication between the main fluid path of the regulator and thediaphragm chamber is provided by the orifice in the orifice plug 31 andalso the significantly smaller fluid connection provided by theclearance between the closure member 14 and the bore of retainer 13. Theclosure member housing or deflection member 11 is shaped so as to causefluid to be deflected around the closure member housing 11 and to enterthe inside of the closure member housing 11 into the region where theclosure member 14 engages with the valve seat 17, via apertures or slots71 in the closure member housing 11, in a plane substantiallyperpendicular to the movement axis of closure member 14. The closuremember housing 11 thus forms a deflection member located in the channeland arranged to deflect fluid flowing in the channel such that theclosure member 14 is shielded to substantially prevent fluid, that isflowing generally parallel to the movement axis of the closure member14, and in a downstream direction, from impinging on the portion of theclosure member that is upstream of the valve seat 17.

In the present example illustrated in FIGS. 1b and 1 c, the closuremember 14 has a conical portion which is referred to as ridge 14 a. Thepresence of the ridge 14 a allows an opening between the closure member14 and the valve seat 17 to be at or between fully open and closedpositions by movement of the closure member 14 along its movement axis.

Movement of the ridge 14 a to a closed position will close a fluid paththrough the regulator and movement of the ridge 14 a away from such aclosed position will open the fluid path through the regulator. Thearrangement of these assembled elements is shown in FIG. 1b and in anenlarged view in FIG. 1 c.

The diaphragm in the present example 21 is formed from a flexible orresilient material such as a moulded elastomer. The diaphragm 21 can bepreassembled so as to be sandwiched between a stud 20 and a spring cup22 by torque tightening the stud 20 into the spring cup 22 to form adiaphragm subassembly 55.

The diaphragm subassembly 55 is installed in the body 10 such that thestud 20 engages with the closure member 14. In the present example, theengagement between the stud 20 and the closure member 14 is provided bylocating the closure member 14 into a recess formed in the stud 20. Inalternative examples, the closure member may be engaged with and/orretained to the stud 20 by providing a gripping engagement of some form,such as by using threaded engagement, barbed engagement or clip. Thediaphragm assembly 55 is assembled into position using a non-threadedgrip ring 30 which in turn has a clamp force applied thereto by torquetightening clamp ring 29 a.

The present example uses a load spring 23 arranged to provide a biasingor load force to the closure member 14 acting counter to the bias spring16 by application of force via the diaphragm subassembly 55 onto theclosure member 14.

To provide an acting surface against which the load spring can act, andto provide for adjustment in the net load force according to the presentexample, a spring guide 25 is fitted to an internal spigot in anadjuster housing 24 which is itself mounted to the main body 10. The fitbetween the spring guide 25 and the spigot of the adjuster housing 24 isa close clearance fit to provide for smooth, unrestricted movement ofthe spring guide 25 over the spigot. The load spring 23 is installedbetween the spring guide 25 and the spring cup 22. An adjuster 26 isthreadedly received through an opening in the end of the spigot of theadjuster housing 24. A ball 28 is received into a hole on the end of theadjuster 26 using an interference fit to form an adjuster and ballsubassembly 56. The adjuster and ball subassembly 56 can be wound in andout along the threaded engagement between the adjuster 26 and the spigotto provide for adjustment in the compression of the load spring 23 bycausing movement of the spring guide 25.

An adjuster subassembly comprises the adjuster housing 24, a springguide 25 and the adjuster and ball subassembly 56. The adjustersubassembly 57 is assembled into the main body 10 and the adjusterhousing 24 is held in place into the receiving structure of the mainbody 10 by a torque tightened clamp ring 29 b.

In the present example, the load spring 23 side of the diaphragm 21 isvented to exterior pressure via a vent hole 100 in the adjuster housing24. The bias spring 16 urges the closure member 14 towards the diaphragmstud 20 thereby obtaining physical communication with diaphragmsubassembly. The net spring force acting on the diaphragm is the loadspring 23 force minus the bias spring force provided by spring 16.

The fluid flow through the pressure regulator illustrated in FIGS. 1a to1c will now be discussed. In use, a fluid enters the pressure regulatorfrom a fluid source connected to the regulator at fluid inlet 70. Thefluid path is deflected around the closure member housing 11. Theupstream end of the closure member housing 11, which is directed towardsthe incoming fluid proximate to the inlet of regulator has, in thepresent example, a conical shape. In other examples, the end of theclosure member housing 11 may have a domed shape, a frusto-conical shapeor a flat profile with chamfers or the like. The fluid path then passesbetween the annulus formed by the bore (receiving structure) of mainbody 10 and the closure member housing 11 and into the chamber insidethe closure member housing 11 through radial holes or slots 71 in theclosure member housing 11.

To set the pressure regulator with the desired outlet pressure set belowthe pressure of fluid supplied to the regulator inlet; the set screw 26is adjusted to obtain a net load force acting on the closure member 14via the load spring 23 and diaphragm subassembly 55 which urges thevalve closure member 14 to provide an opening 72 with the valve seat 17and to allow fluid to flow from the inside of the closure member housing11 through to the radial holes or slots 73 in the valve seat housing 12,into the gallery 74, then to position 75, then into a passage 75 aconnecting to the fluid outlet 75 b. Pressure feedback to the diaphragmchamber 76 is substantially provided by communication of fluid pressurefrom the fluid path at position 75 near the entry to the outlet passage75 a to the diaphragm chamber via the aperture in orifice plug 31. Fluidpressure in the diaphragm chamber 76 will increase until the forceapplied by fluid pressure and the closure member 14 acting on thediaphragm subassembly 55 is sufficient to move the diaphragm subassembly55 to a position towards the left hand side of FIG. 1b such that thetotal force applied towards the left balances with the net load forceacting on the diaphragm towards the right. This balance position of thediaphragm subassembly, and therefore the closure member 14, occurs whenthe opening 72 between the closure member 14 and the valve seat 17 is ofa size that provides the required reduction in fluid pressure from theinlet pressure to obtain a pressure acting on the diaphragm at whichthere is force balance with the net load force.

The pressure regulator therefore operates depending upon the outletpressure to open or close the opening 72 by movement of the closuremember 14 such that the ridge 14 a blocks or provides a variablerestriction to the flow path through valve seat 17. The feedbackpressure control enables the regulator to self-regulate to a set outletpressure. The set outlet pressure can be adjusted using the adjuster 26to vary the net load force acting on the diaphragm.

By providing the configuration shown in FIGS. 1a-1c and as discussedabove, using a deflection member to avoid direct impingement of incomingfluid flow on the closure member in a direction substantially parallelwith the movement axis of the closure member, a compact design ofpressure regulator can be produced having a high maximum fluid flowthroughput.

In an alternate embodiment of the regulator shown in FIGS. 1a-c thevalve closure member can be a ball operating in conjunction with apiston with said ball serving as the closure member acting on valve seat17 and said piston being dimensioned to slidably operate in the bore ofretainer 13 such that the load spring 23 can transmit force to the ballclosure member via the diaphragm subassembly 55. In this configurationone end of said piston is in physical contact with the ball and theother end is in physical contact with the diaphragm subassembly 55.

The above described concepts for producing a compact high throughputpressure regulator can be adapted to produce a pressure regulator with avariety of overall dimensions and flow capabilities. The above describedconcepts may also be used to provide pressure regulating valve for thesecond stage of a two stage pressure regulator valve. However, it willalso be appreciated that although the techniques described herein aresuited to the provision of a compact miniature pressure regulator, suchtechniques may also be employed to make compact larger scale pressureregulators.

The above-described concepts for producing a compact high throughputpressure regulator can be adapted to produce a pressure regulator ofeither the relieving type (where excess downstream pressure is vented tothe exterior of the pressure regulator) or the non-relieving type (whereexcess downstream pressure is not vented to the exterior of the pressureregulator).

Although various components discussed above are described as beingassembled in a particular order or as being held in place by particularstructures, a pressure regulator consistent with the present teachingscan be constructed using a variety of orders and directions of assemblyfor the various components and a variety of securing elements andmechanisms can be deployed. As just one example, it will be apparentfrom the figures that the receiving structure formed in the main body isillustrated in such manner as to indicate that this receiving structurecould be manufactured by milling the receiving structure from the mainbody with the cross-section tending to generally reduce along the axisof the receiving structure.

The principles, preferred embodiments and mode of operation of thepresent invention have been described in the foregoing specification.However, the invention which is intended to be protected is not to beconstrued as limited to the particular embodiments disclosed. Further,the embodiments described herein are to be regarded as illustrativerather than restrictive. The embodiments described above are given byway of example only and modifications will be apparent to personsskilled in the art without departing from the scope of the invention asdefined by the appended claims.

1. A pressure regulator, said pressure regulator comprising a housingcontaining a channel arranged to communicate a fluid from a fluid inletto a fluid outlet, said channel comprising a valve seat and closuremember with said closure member operable with valve seat to controlfluid flow through the channel and; wherein the housing comprises aresilient diaphragm member in fluid communication with the fluid and inphysical communication with the closure member such that the diaphragmmember is operable to deform in response to a change in pressure of thefluid and such that deformation of the diaphragm member causes theclosure member to change position and; wherein that the regulatorcomprises a deflection member located in the channel and arranged todeflect fluid flowing in the channel such that the closure member isshielded to substantially prevent fluid, that is flowing generallyparallel to the movement axis of the closure member, and in a downstreamdirection, from impinging on the portion of the closure member that isupstream of the valve seat.
 2. A pressure regulator as claimed in claim1, wherein that the movement axis of the closure member is substantiallycoaxial with the fluid inlet.
 3. A pressure regulator as claimed inclaim 1, wherein that the deflection member is located in the channelproximate to the fluid inlet.
 4. A pressure regulator as claimed inclaim 1, wherein that the deflection member deflects fluid around theclosure member such that the fluid is directed to the valve seat in agenerally symmetric manner in a plane substantially perpendicular to themovement axis of the closure member.
 5. A pressure regulator as claimedin claim 1, wherein that the closure member comprises a ridge operablewith the valve seat to obstruct the channel when the closure member isin the closed position.
 6. A pressure regulator as claimed in claim 5,wherein that the closure member and valve seat in the channel act topartially define the fluid communication rates in open and closedpositions.
 7. A pressure regulator as claimed in claim 1, wherein thatthe diaphragm member is located away from the channel.
 8. A pressureregulator as claimed in claim 1, wherein that the fluid inlet issubstantially parallel to the fluid outlet.
 9. A pressure regulator asclaimed in claim 1, wherein that the fluid inlet is substantiallyperpendicular to the fluid outlet.
 10. A pressure regulator as claimedin claim 1, wherein that the regulator comprises a bias spring to biasthe closure member into abutting the diaphragm member.
 11. A pressureregulator as claimed in claim 1, wherein that the diaphragm member isbiased by a biasing means to urge the closure member towards a positionthat provides an opening between the closure member and the valve seat.12. A pressure regulator as claimed in claim 11, wherein that theregulator comprises an adjustment mechanism which is operable to adjustthe compression of said biasing means, such that the force acting on thediaphragm member can be varied.
 13. A pressure regulator as claimed inclaim 12, wherein that a section of the diaphragm member which is not influid communication with the channel has a fluid communication path tothe exterior of the pressure regulator.
 14. A pressure regulator asclaimed in claim 11, wherein that said biasing means comprises apressurised control fluid which acts on a section of the diaphragmmember which is not in fluid communication with the channel.
 15. Apressure regulator as claimed in claim 14, wherein that the pressure ofthe pressurised control fluid can be adjusted to vary the force of thepressurised control fluid acting on the diaphragm member.